A Three-Phase AC Input Induction Heating System With Heat Distribution Control Capability

This article proposes a new three-phase ac input induction heating (IH) system for plate heating. The proposed system consists of three sets of a direct ac-ac converter and a pancake-shaped work coil. Each phase uses the set of the converter and the coil. In the proposed system, the three work coils are arranged in a triangular shape with a certain distance to eliminate mutual induction between them. Therefore, each converter can operate independently. The proposed system uses this independence to realize a power factor correction (PFC) operation of ac-line currents. Also, the proposed system can control heat generation on a workpiece above a center of the three coils by using the independence. The proposed system with heat distribution control capability is theoretically considered, and it is also validated experimentally. As a result, the proposed system demonstrates both the PFC operation of the ac-line currents and heat distribution control at the rated power of 3 kW.